The driving of DC motors, for ventilation in climate control units, is provided normally by means of electromechanically-switched DC devices, in which the coil is supplied by the same switching voltage as the load. These electromechanical devices are normally expensive, require dedicated wiring and are subject to mechanical wear. Further, depending on the power of the DC motor, it is necessary to arrange suitable protective devices, such as electromechanical switches of the magnetothermal type.